The Caddy EcoFuel uses what Volkswagen calls a quasi-monovalent approach: optimized for operation on natural gas, it has a small 13-liter (3.4 gallons US) tank for gasoline operation. The engine always starts using gasoline.

The engine has a relatively high compression ratio (13.5:1) for operating with natural gas. When running on gasoline, the ignition point is delayed and the throttle butterfly setting adjusted to compensate for the high compression.

Four storage tanks hold 26 kg of natural gas, and are located in the rear under the floor. The underfloor storage maximizes interior space for cargo or passengers.

Comments

Vehicles fueled via excess hydrocarbon gas emissions from landfills, (and possibly captured from melting permafrost in the future) there could be a substantial and sustained niche class. The engine tech is already matured, and the existing problems are solvable by relatively inexpensive, safe and environmentally benign solutions, for the most part.

Kind of strange. NG engine has distinct advantage over gasoline at engine start and heating-up. NG does not have gasoline troubles to evaporate in cold engine, so overriching the mixture is not needed. This cut the HC pollution quite substantially, and reduces fuel consumption too. Other manufacturers manage to start NG engines without any troubles. Actually it is even easier at cold weather.

allen Z and sjc: The supplies of waste-derived biomethane fall many times short of what aircraft would require, let alone motor vehicles. The price and ecological impact are determined at the margin; you need a substantial surplus of clean fuel to guarantee that the whole is earth-friendly.

Biomethane can be derived or synthesized. You can make syngas out of biomass using several technigues. Once there is an even larger market for methane and the economics of importing LNG in tankers becomes obvious, making methane out of syngas may prove cost effective.

Engineeer-Poet,
"The supplies of waste-derived biomethane fall many times short of what aircraft would require, let alone motor vehicles."
_
_I said niche. We also did not mention aircraft. Additionally, if Swedes could pull off the shift over to biomethane, then there could be an source.

Dear Sir,
Iam intrested in this car. please send me the technical details of this car's engineand machanism because i have an idea to create more benificial this car. also i want to use this car personaly. please send me some grafical vidioes of this car.and how can you available me this in india. please send me earliar.
Bhaskar A. Vyas